Nitrite standard dilution¶
Below are methods for preparing 5 mL nitrite standards. Adjust volumes as necessary for preparing larger volumes. The first step is preparing a working stock by diluting a commercially available nitrite standard. This working stock is then diluted further resulting in a set of 8 nitrite concentrations (plus a distilled water blank).
In addition to the equipment listed on the appropriate nitrite assay page, you will also need the following equipment and reagents if you plan to collect nitrite calibration data:
- 1,000 ppm N (3,280 ppm as NO2) standard, Labchem Cat # LC17930-7
- 1 mL variable micropipette
- 2 x 100 mL volumetric flask for preparing the working stock
- 5 mL sample tubes
- Distilled water
Nitrite range (0 - 2 ppm NO2)¶
- Volume: 5 mL
- 100 ppm NO2 working stock #1: 3.05 mL of the 3,280 ppm (1,000 ppm as N) standard in 100 mL distilled water in volumetric flask. Fill to the line with distilled water.
- 2 ppm NO2 working stock #2: 2 mL of the 100 ppm working stock 1 in 100 mL distilled water in volumetric flask. Fill to the line with distilled water.
| Tube | NO2 concentration (ppm) | Volume of 2 ppm working stock #2 (mL) | Volume of distilled water (mL) |
|---|---|---|---|
| 1 | 0.00 | 0.000 | 5.00 |
| 2 | 0.25 | 0.625 | 4.375 |
| 3 | 0.50 | 1.250 | 3.75 |
| 4 | 0.75 | 1.875 | 3.125 |
| 5 | 1.00 | 2.500 | 2.50 |
| 6 | 1.25 | 3.125 | 1.875 |
| 7 | 1.50 | 3.750 | 1.25 |
| 8 | 1.75 | 4.375 | 0.625 |
| 9 | 2.00 | 5.000 | 0.00 |